Introduction

This example shows how to get the Option Globetrotter HSDPA USB Modem working with LMT (Latvian Mobile Telephone UMTS/GPRS networks), or with Amigo (GPRS network) in Latvia. Service in your country might have different requirements and strings, but this is just to give you an outline of what is required.

Prior RouterOS V3.23, a modem had all its ports listed. Since V3.23 there is one port per modem, and modem has channels used for commands and data. Channels have numbers 0,1,2, etc. Some modems may have just two channels, some have more. Set the baud rate to 9600 for communicating with the modem, in case it's not done already:

Workaround for Globetrotter devices offering no modem interface

There is no guarantee that the commands above work on all the modems that need the HSO driver. The tested device was a T-Mobile branded Globetrotter iCON 225 "web'n'walk Stick". That device was able to connect without problems after the method described. Some Globetrotter HSDPA cards, for example the iCON 225 (branded as Orange, T-Mobile web'n'walk stick, etc. have the serial modem interface disabled by default, and only offer an NDIS network interface for the data connection. If a dial command is issued, but no CONNECT response happens from the modem, it might be helpful to check this. To check on the setting, issue:

Number of channels should have increased. On the tested device, the last channel is the modem-interface (number 3 in RouterOS).

According to [1] the Linux HSO driver page at least five Option devices exist which do not have the modem interface enabled by default.

Router Configuration for PPP

Since RouterOS V4 (and latest versions 3) the PPP client configuration is made much easier compared to previous versions. There is no need to use ppp profiles, and ppp-client interface might have been added automatically to the /interface ppp-client list:

The interface has 3G/GPRS modem specific arguments, like apn, pin. Consult your network provider what to use for APN, user, and password. Adjust your peer-dns and default-route settings according to what you want to do over that interface! In our case, we want permanent connection and won't use dial on demand:

You can get more status information about the modem and network by running the "info" command. In our case the modem uses the same channel for data and info, thus, we disable the ppp-client and run the "info" command then:

The _OPSYS operation mode setting stays intact after router reboot or power off/on. If you lock the modem operation setting to 3G only, the scan command won't show GPRS networks, and vice versa.

Troubleshooting

You do not get "authenticated" and "connected"

There is something wrong with your settings. Most likely, the ppp-client interface settings should be changed to match your provider's requirements.

If the data-channel setting is wrong, there will be no connection. The number of available channels is shown under the /port list, port numbers start with 0. Disable the interface and try another port number!

Check if you can communicate with the modem by using the serial-terminal! Make sure the ppp-client is disabled!

Turn off PIN request for your SIM card, it makes the life much easier. Do it in a phone if you do not know the correct AT command.

Speed of the link is not what expected

It's possible that the modem has connected to GPRS network, not 3G. Use the "scan" command for list of available networks: